Obesity has reached epidemic rates in the U.S. Estimates indicate that one third of the adult population is at risk for adverse health consequences resulting from obesity and overweight. Early prevention efforts are essential because the risk of an overweight child or adolescent becoming obese as an adult increases with both age and degree of overweight. Data suggest that youth who are above average weight are at greater risk than their average weight peers for future excessive weight gain and the development of obesity-related co-morbid conditions. The most prevalent disordered eating pattern described in overweight and at-risk for overweight adolescents is loss of control (LOC) eating, during which individuals experience an inability to control the amount of food they consume. Evidence indicates that LOC eating episodes, even occurring infrequently (=1 times/month), predispose youth to gain excessive weight. Thus, LOC eating is likely to be an important contributor to obesity in susceptible individuals. Efforts to decrease LOC in adolescents are potentially preventive interventions. However, it remains unknown whether LOC eating can be decreased by preventive efforts in adolescents, or whether programs directed at reducing LOC eating affect weight gain trajectories. Interpersonal Psychotherapy (IPT) has been adapted for the treatment of eating disorders and has demonstrated efficacy in reducing binge eating episodes and inducing modest weight loss or weight stabilization among obese adults diagnosed with binge eating disorder. IPT, which targets the underlying social and interpersonal difficulties that predispose individuals to engage in LOC eating, is also well-established and effective for the treatment and prevention of depression in adolescents. In a pilot study, IPT was found to be feasible and acceptable in slowing the trajectory of weight gain in overweight or at-risk for overweight adolescents who report symptoms of LOC eating. Preliminary findings are promising and thus require an adequately powered trial to determine whether IPT is effective at preventing excessive weight gain in youth at high-risk for adult obesity who report LOC eating. Accordingly, the proposed study is a controlled trial randomizing 110 adolescent (12-17y) girls between the 75th and 97th BMI percentile to either IPT or a standard-of-care health education program. BMI will be assessed prior to and just after the prevention programs, and again at 6 and 12 month follow-up visits. Pre and post measures of LOC eating, disordered eating attitudes, and general psychopathology will be collected. Additionally, measures of actual food intake based upon laboratory test meals will be collected before and after the programs. If IPT proves effective in reducing excessive weight gain attributable to LOC eating, it may provide an important early intervention to prevent the adverse health consequences of adult obesity. PUBLIC HEALTH RELEVANCE: Preventing excessive weight gain in adolescents at high risk for adult obesity has important relevance to public health. By decreasing the number of individuals who become obese in adulthood, the economic burden of co-morbid health conditions and psychological problems may be reduced. Given that weight loss programs have been met with minimal success, prevention of excessive weight gain before adulthood must be a priority in order to reduce the epidemic rates of obesity.